Potty training, peeing underwear?

Bri

I am trying to potty train my almost 3 year old boy. He really does amazing during the day, he just goes around naked (no diaper or undies). But as soon as a diaper or underwear is on he’ll pee. I really don’t know where to go from here? He can’t be naked all the time (obvi) or else I wouldn’t care. Any suggestions?